


waterproof, shatterproof

by Cerberusia



Category: Teen Wolf (TV)
Genre: Age Difference, Knotting, M/M, Size Kink
Language: English
Status: Completed
Published: 2013-03-10
Updated: 2013-03-10
Packaged: 2017-12-04 21:05:56
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,914
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/715093
Author URL: https://archiveofourown.org/users/Cerberusia/pseuds/Cerberusia
Summary: <blockquote class="userstuff">
              <p>They're closer than they've ever been, closer than Isaac's ever been to anyone, and somewhere along the line the boundaries get blurred.</p>
            </blockquote>





	waterproof, shatterproof

**Author's Note:**

  * For [hagiologic](https://archiveofourown.org/users/hagiologic/gifts).



> For the lovely hagiologic, who won me (three times over, as a matter of fact) in the Sterek Campaign Auction and has been very patient with my ridiculous schedule. Have no fear, your Sterek and Baby Beta OT3 are in the works...The title is from Plath's 'The Applicant', because I'm on a Plath kick right now. Should anyone be wondering why certain werewolves have knots and others don't in this universe, I restricted it to born werewolves.

At six-one, Isaac is used to being taller than most people. Not necessarily by much, just a couple of inches on most of the lacrosse team, but enough to make him uncomfortably aware of how gangly and awkward he is. This, combined with a deeply ingrained desire not to be noticed, makes him duck his head and slouch most of the time. It's probably doing terrible things to his back, but when you're not entirely sure you'll live to see your next birthday, future orthopaedic problems are of limited concern.

He doesn't expect to be taller than Derek, though. His first sight of him is a tall, dark and handsome man, looming above him - offering him a hand up, out of the grave he's dug. There's poetic irony in there somewhere, but Isaac doesn't like to dwell on it.

But nope, he's got a solid inch on Derek when he actually stands up straight. Only heightwise, though - werewolf-induced muscle mass increase or no, he'll never be that broad and he's okay with that. He'll stick with being wiry and fast and able to find clothes without having to consider whether they'll fit his shoulders, thanks.

Besides, if he was bigger than Derek he'd probably be the one doing the carrying, and for all he grumbles about being picked up like a bride (in reply to which Derek always asks whether he'd like to be picked up like a sack of potatoes instead?), that's one of his favourite things, because Derek is big and solid and warm and _safe_. It's not perfect, mind, because of the height thing, but the mental comfort outweighs the lack of physical same.

It's just one of their things, these days: Isaac is the only Beta Derek has left, so Derek turns all his attention on him. And apparently all his affection - it's Derek who invites Isaac to sleep in with him now that he can't sleep in a pile with Boyd and Erica, not waiting for Isaac to come crawling as he would have inevitably done. Sometimes Derek's there when Isaac wakes in the morning and sometimes he's not, but he always starts the day covered with his Alpha's scent.

They're closer than they've ever been, closer than Isaac's ever been to anyone, and somewhere along the line the boundaries get blurred. For instance: sometimes, if Derek's not there in the morning, Isaac jerks off in the bed. Although he's careful not to get anything on the sheets, Derek must still surely be able to smell it - but he doesn't say anything the first time, nor the second or third, and it becomes normal.

Then he starts doing it even when Derek _is_ there. He's half asleep the first time, and only realises that the reason Derek's smell is so strong is because he's right next to him when it's over. Derek, praise every deity that Isaac doesn't actually believe in, is still asleep.

Isaac gets a shock when the second time he tries it, this time rather more lucid, he opens his eyes to find Derek looking back at him, eyes half-lidded with sleep. Isaac freezes, shocked into full wakefulness. But Derek just blinks at him then rolls over onto his side, his back to Isaac. And Isaac understands the implicit permission, and listens to Derek's steady heartbeat as he finishes getting himself off. It's weird, unbelievably weird, but Isaac stopped caring about appearing normal when he got the Bite.

Soon enough, it turns seamlessly into Derek watching him: his face, his hunched shoulders, his hand beneath the sheets. He doesn't know what Derek thinks about it and hasn't the courage to ask, so they keep this equilibrium for a while: Derek looking, but never touching. Never even looking like he wants to. He's just totally not bothered by a teenage boy rubbing one out only inches away.

If it were anyone else, Isaac would push. He's gotten good at that, after the Bite. But Derek sometimes makes him feel like he did before, when there was someone to make proud, or to try to. He also kind of wants to see Derek naked, but he figures not screwing up his relationship with his Alpha (and the only other member of his pack) is more important.

So he leaves it alone. It'll go away (but then he thought that when Dad started getting weird, and look what happened - but he doesn't think about that any more). A couple of times he thinks Derek's eyes get a little hotter when he takes his shirt off briefly to change into a big t-shirt - which might be Derek's, come to think of it - for sleeping, but he's pretty sure that's only wishful thinking.

Then he wakes up one morning, casually touches himself - and one big, warm hand lands on his thigh and it takes him a couple of seconds to recalibrate his expectations but once he does, he's totally on board.

They move fast: one handjob, followed by Derek rutting against Isaac's thigh, then when Isaac comes back from school Derek actually _lifts him off his feet_ into a kiss and Isaac has to wrap his legs around Derek's waist to keep his balance. Which is ridiculous, considering he's taller, but that's Derek for you: always has to make a statement.

Isaac isn't expecting them to fuck, but they do. Derek's kind of rough about it actually, like he's been waiting a long time. He probably has - Isaac's at least ninety eight percent sure that Derek hasn't had sex in all the time Isaac has known him. Seems like the frustration of having a willing teenage boy jerking off right under his nose most mornings finally got to him.

Isaac's never had anything up his ass before, so he's glad that Derek takes the prep a bit slower. He must have done this before, but he looks kind of virginally-nervous. Definitely been a while. He's very hesitant about getting his cock out, almost shy until Isaac rolls his eyes, sits up, crawls into his lap and makes his intentions very clear by pressing his ass against Derek's dick until he gets the message and slicks himself up. He doesn't roll Isaac over like he was expecting, but instead keeps him on top, straddling him, and lets Isaac control the pace at which he takes his cock.

Slowly, as it turns out - he wants to go faster, get the initial pain out of the way, but his body has other ideas: he gets the head in, then his ass clenches and just refuses to go any further until he pauses, draws himself up a little and tries again: another half an inch. He keeps doing that: another inch inside, up half an inch, let himself slip down an inch, keeping himself balanced on the agonising edge of pain and pleasure.

Almost there, Derek's dick feels very big inside him. Isaac takes harsh breaths through his nose and gradually sinks down the last half-inch. He settles there, straddling Derek, knees flexing against his sides like heels against a pony's flanks. It feels incredibly weird and not a little painful, though werewolf healing takes out a lot of the sting. He wriggles a bit, experimentally, then promptly has to steady himself because yeah, he needs a couple more minutes to adjust.

Derek stays still, even motionless, a rock but for the rise and fall of his chest and his fluttering eyelashes - and the pulse of his dick inside Isaac, shockingly intimate. Isaac tries to relax, but he can't stop squeezing, muscles contracting and relaxing around Derek's dick without his control.

"Here," says Derek, quietly, gruffly, and raises one hand to wrap it around Isaac's cock. As distractions go, it's a good one: Isaac stops focussing on the stretch to concentrate on Derek's warm, big hand instead.

But the best part is when, slowly, Derek raises his other hand to rest it on the small of Isaac's back, just above his ass, palm radiating heat into his very core. Isaac's not small, not any more, but Derek's splayed fingers cover most of the breadth of his back and the feeling of reassurance they bring is indescribable.

It goes easier, after that. Isaac feels that he should be riding Derek properly, like they do in porn - he's strong enough to do all those squats now - but this is probably the only time they'll ever do this before Derek remembers what a terrible idea it is, so he's selfish instead and does it how he wants it: just squirming really, circling his hips, lifting himself maybe half an inch then grinding back down. Derek just jerks him through it, hands steady even as his cock throbs inside Isaac. His breathing is rough, rougher than Isaac's, who is silent. Maybe, when Isaac's done, he'll flip him over and take him properly, fuck him like he must be restraining himself from doing, and Isaac all loose and fucked-out and oversensitive-

Isaac bites his bottom lip as he comes on Derek's stomach, hips jerking but barely feeling Derek's dick inside him. He drops forward to rest his hands on Derek's chest, torso curved over Derek's like a comma. He doesn't get to enjoy the afterglow though, because Derek immediately lets go of his cock to seize his hips and start shoving - what the hell is _that_? It's like he's trying to get a baseball up there. Why the fuck is there a baseball-sized _thing_ in his cock?

He doesn't say anything, of course, he's not stupid: just watches Derek's face, his eyes screwed up in concentration as he slowly, steadily presses the swelling into Isaac's ass. And it's a good thing he's still riding on endorphins, because otherwise this would hurt like a _bitch_. As it is, it's back to that weird pleasure/pain feeling, like he's being filled too far but offset with these little pleasurable shocks.

Finally, it's in. Isaac hopes it doesn't have to come in and out several times, and apparently the fortunes are smiling on him today because Derek just clutches him, arches his hips (with Isaac still sitting on them, Christ, he can see Derek's abs tensing and it's hypnotising), grinds his cock deep into Isaac and goes still. Isaac watches his face as he comes and doesn't feel at all creepy for trying to memorise it.

At last, Derek opens his eyes.

"Sorry," he says. "I didn't mean to, uh." He gestures vaguely to where they're joined. "We're, uh, going to be stuck together for a few minutes. I mean, I can take it out now, but that'll hurt."

"It's fine." He doesn't know why Derek's so uncharacteristically nervous all of a sudden, but it's not really his business. Carefully, he leans forward to lie on top of Derek: Derek'll tell him if he doesn't like it. But Derek instead hesitantly raises his hands to put them first midway down his back, then slides them down to rest, one on top of the other, at the small of his back. And the two of them lie there, one on top of the other, and Isaac is so intensely glad for strange quirks of Derek's biology he could kiss him. He settles for burying his face in the side of Derek's neck and inhaling the smell of sweat and Alpha, and finally lets himself relax.

If Derek feel his small, private smile against his neck, he doesn't say anything, just keeps holding onto him.


End file.
